Such a skin treatment device is, e.g., disclosed in the United States patent application published as US 2012/0197357 A1. Said skin treatment device comprises a laser source and an optical pattern generator for creating microscopic treatment zones (MTZs) of thermally denatured skin tissue surrounded by unaffected skin tissue. This treatment boosts skin repair mechanisms and improves skin appearance. An axicon wheel with a plurality of axicon segments deflects the laser beam towards a corresponding plurality of different locations on the skin surface. A control circuit controls the laser source to randomly illuminate individual axicon segments. While the user drags the device along the skin surface, a random pattern of MTZs is applied to the skin surface. An intensity level set by the user determines the density of the random pattern.
In the known device, every axicon facet has a triggering flake that is detected by a flake detector upon passing the flake detector during rotation of the axicon wheel. The flake detector is coupled to the control circuit, which determines the rotational speed of the axicon wheel, based on the flake detector signal. Based on the rotational speed of the axicon wheel and a measured speed at which the user drags the device along the skin surface, the control circuit is able to provide the randomly distributed MTZs at a more or less constant density.
Although the possibility to set an intensity level does provide some control over the operation of the device, there is still a need for improving treatment control to better adapt to differences in skin type, skin condition, skin treatment and user preferences. It may, e.g., be desirable to make the operation of the device more specific for certain skin features, such as wrinkles, fine lines or pigmented spots.